Tải bản đầy đủ - 0 (trang)
Spawning Areas and Larval Dispersal and Recruitment Strategies of Anguillid eels in the Indo-Pacific, Michael Miller [et al.]

Spawning Areas and Larval Dispersal and Recruitment Strategies of Anguillid eels in the Indo-Pacific, Michael Miller [et al.]

Tải bản đầy đủ - 0trang

Temporal dynamics of the recruitment of

three eel species in French Polynesia

Herehia Helme



∗ 1



1



Ecole Doctorale 472 : Syst`emes Int´egr´es, Environnement et Biodiversit´e (EPHE) (ED 472 SIEB) –

Ecole Pratique des Hautes Etudes – Ecole pratique des hautes ´etudes Ecole doctorale 46 rue de Lille

75007 Paris, France



Eels still represent a great mystery with their diadromous catadromous life cycle; they breed

at sea and larvae migrate to fresh waters to grow and spend their adult life. In French Polynesia,

eels are emblematic both ecologically, as top predators in rivers, and culturally as, according

to Polynesian legends, they represent the creation of life. There are three species known in

French Polynesia: Anguilla marmorata the ”marbled eel”, A. megastoma, the”mountain eel”

and A. obscura, the ”mud eel”. The present study is the first long-term follow-up (3 years)

of the temporal dynamics of the recruitment of the three species in the valley Papenoo, the

biggest of Tahiti island. The arrival of glass eels throughout the year was monitored; the species

composition of the recruits and the state of the populations were assessed, enabling us to study

the recruitment variation. This study also analysed environmental variables that may affect the

recruitment. Our results revealed (i) a seasonal recruitment occurring during the new moons

of the wet season from November to March with a peak between December and January, and

(ii) that the three species arrive in the estuaries at the same period. This monitoring should be

continued to improve our knowledge of the status of the populations of the three species found

in French Polynesia. It should also be carried out over several rivers in order to compare the

results.







Speaker



350



The leptocephalus larvae/marine snow

food-web theory: pros, cons and

uncertainties after 20 years of investigations

in the Indo-Pacific.

Eric Feunteun ∗ 1,2 , Michael Miller 3 , Chistine Dupuy 4 , Alexandre

Carpentier 5 , Anthony Acou 2,6 , Mari Kuroki 7 , Aur´elie Dessier 4 , Shun

Watanabe 7 , Jun Aoyama 7 , Tsuguo Otake 7 , Katsumi Tsukamoto 3

1



Biologie des Organismes et Ecosyst`emes Aquatiques (BOREA) – Museum National d’Histoire

Naturelle, Universit´e Pierre et Marie Curie - Paris 6 : UM95, Centre National de la Recherche

Scientifique : UMR7208 – 7, rue Cuvier, CP 32, 75231 Paris Cedex 05, France

2

Mus´eum National d’Histoire Naturelle - Centre de Recherche et d’Enseignement sur les Syst`emes



otiers, Dinard, France (MNHN - CRESCO, Dinard, France) – Museum National d’Histoire Naturelle MNHN (FRANCE) – 38 rue du Port Blanc, 35800 Dinard, France

3

Laboratory of Eel Science, Nihon University, Japan – 1866 Kameino, Fujisawa-shi, Kanagawa,

252-0880, Japan

4

UMR - Liens, University of La Rochelle, France – UMR LienS - University of La Rochelle, France –

Bat Ile, 2 rue Olympe de Gouges 17 000 La Rochelle, France

5

Universit´e de Rennes1 – Universit´e de Rennes 1 – MNHN-CRESC0, 38 rue du Port Blanc, 35800

Rennes, France

6

MNHN - Unit´e Mixte de Service Patrimoine Naturel (UMS PatriNat) – Mus´ee National d’Histoire

Naturelle - MNHN (France) – MNHN - CRESCO, 38 rue du Port Blanc, 35800 Dinard, France

7

the University of Tokyo – 1-1-1, Yayoi, Bunkyo, Tokyo 113-8657, Japan



Since the epic Danish around-the-world oceanographic cruise to collect leptocephali in 19381939 led by Johannes Schmidt, the intertropical oceans have been known to host a high diversity

and abundance of larval stages of anguilliform and elopomorph teleosts: the leptocephalus larvae.

They all share striking morphological features: large eyes, a transparent laterally flattenedbody with only a thin muscle-layer. Some species reach lengths of > 30 cm and ages of several

months to > 1 year. Leptocephali are part of the micronekton that are mainly found in the

ocean epipelagic layers. Despite these common features, little is known about their diet. Direct

observations of thousands of specimens show that the majority of their guts are seemingly empty,

but instead contain an apparent paste that could be consumed organic matter. Currently the

leading hypothesis is that marine snow provides most of this organic matter paste. Marine Snow

is formed by the agglomeration of a wide range of biologically produced and discarded materials

that slowly sink while being processed and recycled to nutrients by a complex ecosystem of

microorganisms and direct consumers. We examine the historical and unpublished findings of

an unprecedented research effort resulting from 4 research cruises conducted in the Southwest

Indian Ocean in 2006 and 2010 and the South Pacific Ocean in 2013 and 2016 that used d15N

and d13C isotopic ratios and fatty acid signatures in leptocephali and particulate organic matter

(POM). We compared those biochemical tracers obtained from hundreds of leptocephali from





Speaker



351



7 families to planktonic and micronektonic organisms and POM that contains marine snow.

These results clearly show that all leptocephali seem to have a similar feeding ecology, which is

at lower trophic levels than all micro-zooplankton, suggesting that they are part of the detrital

food web. However, the findings using d15N and d13C ratios and fatty acid profiles that some

taxa of leptocephali occupy different ranges of trophic positions in the lower food web, suggests

there are mechanisms limiting competition for the same food sources or feeding depths. This

identifies new research objectives to understand the role of soluble organic matter (i.e. TEPs)

contained in the marine snow.



352



E2/ Cryptobenthic fishes: Ecology

and evolution of the smallest marine

vertebrates



353



A wonderful radiation of cryptobenthic

clingfishes along Australia’s Southern Coast

Kevin Conway



∗ 1



, Cragen King 2 , Glenn Moore



3



1

Dept. of Wildlife and Fisheries Sciences, Texas AM University – Rm 232, Wildlife, Fisheries

Ecological Sciences Building (WFES), 2258 TAMU 534 John Kimbrough Blvd, College Station, Texas

77843-2258, United States

2

Marine Biology Interdisciplinary Program, Texas AM University – Rm 232, Wildlife, Fisheries

Ecological Sciences Building (WFES), 2258 TAMU 534 John Kimbrough Blvd, College Station, Texas

77843-2258, United States

3

Western Australian Museum – Perth, Australia



Clingfishes of the family Gobiesocidae ( ˜165 species and 50 genera of largely uncertain relationships) are archetypal cryptobenthic fishes. Fifteen species of clingfishes are found in the

shallow temperate marine waters along Australia’s Southern Coast, representing seven described

and three undescribed genera. This Southern Australian clingfish fauna not only includes ”typical” looking clingfishes (e.g., Aspasmogaster, Cochleoceps and Creocele) but also diminutive

macroalgae and seagrass specialists (e.g., certain members of Cochleoceps, Parvicrepis and Posidonichthys), commensal cleaners (Cochleoceps), and strange eel-like forms (Alabes). Preliminary

phylogenetic analyses of a multi-locus data set for over 80 species and 40 genera of clingfishes

have uncovered a large clade comprising a subset of Southern Australian taxa, including Alabes, Cochleoceps, Parvicrepis, Posidonichthys, and the undescribed Genus A, B and C. Within

this clade, Cochleoceps and Genus A are not recovered as monophyletic and the strange eel-like

Alabes are recovered in a sister group relationship with the diminutive macroalgae specialists

Parvicrepis and Genus B. The diversity of body shapes and sizes, habitat specializations and

behaviours represented within this Southern Australian clade is unparalleled within the Gobiesocidae. An overview of this diversity as well as potential morphological characters that provide

evidence for this clade of quintessential cryptobenthic fishes will be provided.







Speaker



354



Coral-Gobies as a Model System for

Understanding the Evolution and

Maintenance of Sociality

Marian Wong

1



∗ 1



, Martin Hing† 1 , Selma Klanten 2 , Mark Dowton



1



Faculty of Science, Medicine and Health [University of Wollongong] (UOW) – Northfields Ave,

Wollongong NSW 2522, Australie, Australia

2

University of Technology Sydney (UTS) – 15 Broadway, Ultimo NSW 2007, Australia



The phenomenon of sociality, whereby independently reproducing individuals came together

to form one cooperative unit, has posed an evolutionary conundrum to biologists over many

decades. This is because those individuals, once capable of reproducing, gave up their reproductive rights in order to become part of a social group. Despite many excellent theoretical

and empirical studies testing key concepts of social evolution theory, there is still debate regarding the relative importance of various factors favouring sociality, suggesting that there may

not be a general explanation. Here, we discuss two potential improvements in the study of

sociality that could aid in the progress of this field. The first relates to the choice of model

system which has largely been biased towards terrestrial animals in the literature. In contrast,

recent consideration of other taxa, particularly marine taxa, is slowly revealing that expanding

our perspective can enhance our understanding of these concepts and generate novel insights.

The second improvement relates to the incorporation of a broader approach to testing concepts,

by using different methodologies – namely observational, experimental and phylogenetic protocols, to test predictions of key hypotheses. We illustrate how these two improvements have

been enmeshed in one specific group of marine coral-reef fishes, the coral-dwelling gobies (genus

Gobiodon). These species reside permanently within corals and exhibit a wide array of social

systems, being either strictly pair-forming (asocial) or highly gregarious social groups (social).

We develop a phylogeny on which we map i) an index of sociality and ii) ecological variables

for each species to demonstrate the evolutionary progress of social evolution and whether they

are related to ecological factors (and key hypothesis). We then propose experimental work on

these coral-goby species to accompany the phylogenetic comparisons. Therefore, by combining

investigations of under-studied coral reef taxa with multiple methodologies, we can provide a

more holistic approach towards understanding social evolution in animals in general.









Speaker

Corresponding author: mlh913@uowmail.edu.au



355



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Spawning Areas and Larval Dispersal and Recruitment Strategies of Anguillid eels in the Indo-Pacific, Michael Miller [et al.]

Tải bản đầy đủ ngay(0 tr)

×